3D is the cleanest material Plainsman mines in the Whitemuds (lowest fired speckle and low soluble salts). It is silty and has traditionally been used to cut plasticity in bodies. It is the bottom layer, that we mine, the thickest, but we have so much of it stockpiled that it has not been extracted in the past two minings. But recently we have discovered that if slurried and sieved to 325 mesh, the quartz particles are removed leaving a plastic ready-to-use porcelain for the 6-8. One that fires to steel-like strength.
The front tile was fired vitreous and strong at cone 01 (2050F) from a clay mined in Elkwater, Alberta (98Mix). It is fine grained and plastic, clean and low in soluble salts. The back tile is made from a silty clay from Ravenscrag, Saskatchewan (3D). It fires vitreous at cone 6 (2200F). The glaze on that tile is made using a high percentage of another clay similar to 98Mix, it melts at the higher temperature of 2200F. These tiles have dried and fired flat despite the fact they were made from plastic clay (rather than dust pressed).
Plainsman extracts 6 different sedimentary clays from this quarry (Mel knows where the layers separate). The dried test bars on the right show them (top to bottom). The range of properties exhibited is astounding. The top-most layer is the most plastic and has the most iron concretion particles (used in our most speckled reduction bodies). The bottom one is the least plastic and most silty (the base for Ravenscrag Slip). The middle two are complete buff stonewares made by mother nature (e.g. M340 and H550). A2, the second one down, is a ball clay (similar to commercial products like OM#4, Bell). A2 is refractory and the base for Plainsman Fireclay. The second from the bottom fires the whitest and is the most refractory (it is the base for H441G).